Abstract:
Krimpsiekte, an economically important neuromuscular affliction of small
stock, follows upon ingestion of certain members of the Crassulaceae
(plakkies) containing cumulative neurotoxic bufadienolides. Tylecodon
wallichii (Harv.) Tolken subsp. wallichii is probably the most
important species of the group of plants causing krimpsiekte. The
growing tip of the stem and various other plant parts of T. wallichii,
when available, were collected monthly. The seasonal variation in
cotyledoside content of the plant was measured. Cotyledoside
concentration was determined by high performance liquid
chromatographic-electrospray mass spectrometry analysis (HPLC-ESMS). The
cotyledoside concentration in the plant stems fluctuated substantially
during the year, but tended to be higher in the cold winter months and
increased again in the spring and early summer. Elevated plant stem
concentrations corresponded with natural field outbreaks of krimpsiekte,
which usually occur during the winter to early summer. The highest
cotyledoside concentrations were detected in the flowering stalk.
Cotyledoside was not the only component of this type in the plant, as
mass spectrometry revealed the presence of other, possibly related,
compounds.
